Welcome Presentation Presentation Q & A (General) Focus ......Presentation (Eric Thompson, MSA...
Transcript of Welcome Presentation Presentation Q & A (General) Focus ......Presentation (Eric Thompson, MSA...
6:00 – 6:15 Welcome 6:15 – 6:55 Presentation6:55 – 7:15 Presentation Q & A (General)
7:15 – 7:45Focus Group Discussion/Zoom
Breakout Rooms7:45 – 8:00 Come Together/Wrap‐Up
Watershed Studies 2020City of Madison Engineering Division
Evening Overview
Welcome (Lauren Striegl, City of Madison)
Presentation (Eric Thompson, MSA Professional Services)
Q&A (facilitated by Lauren Striegl, City of Madison)
Wrap Up (Lauren Striegl, City of Madison)
Breakout to Small Groups (City of Madison & MSA Staff)
1. Why We Are Here2. 100‐Yr Storm Definition3. Where the Water Goes4. Reasons for Flooding Issues5. Watershed Study Goals6. Next Steps7. Property Owner Responsibilities8. How to Stay Involved
Presentation Overview
Wisconsin's Changing Climate: Impacts and Adaptation. 2011. Wisconsin Initiative on Climate Change Impacts. Nelson Institute for Environmental Studies, University of Wisconsin‐Madison and the Wisconsin Department of Natural Resources, Madison, Wisconsin.
More rain
More rain events greater than 3”
Why We Are Here: Historic Events
Recent Rain Events
July 21, 2016: 2.18” in ~3 hours
July 10, 2017: 2.74” in ~2 hours
June 16, 2018: 2.49” in ~3 hours
August 20, 2018: 5.94” in ~9 hours
July 9, 2020: 1.72” in ~3 hours
Why We Are Here: Historic Rain Events
All rainfall totals taken from the Weather Underground Sunset Village station (KWIMADIS33) in Madison, WI.
E Johnson Street, Madison, WI
KMKX Radar that was “bias corrected” using rain gauges by UW Professor Dan Wright
Rainfall Totals August 20‐21, 2018
Recent storms have amplified known inadequacies
Recent storms have revealed new storm sewer deficiencies
Result: flood damage
Why We Are Here: Historic Rain Events
Deming Way, Madison, WI
August 20th event: substantial damage Public infrastructure: $4 million
Private property: reported $17.5 million, estimated $30 million
Why We Are Here: Historic Rain Events
Odana Road (above), Glenwood Children’s Park (right), Madison, WI
Most damage on the West Side
Mostly residential damage
Some commercial damages
Big losses!
Recent storms have amplified known inadequacies
Recent storms have revealed new storm sewer deficiencies
Result: flood damage
City’s plan Complete watershed studies of impacted areas
Develop solutions from watershed studies
Why We Are Here: Historic Rain Events
Deming Way, Madison, WI
100‐Year Storm Definition
Annual exceedance probability (AEP): chance that a rainfall event will occur in one year.
100‐yr storm = 1/100 (1%) AEP Does NOTmean that a storm will only occur once in 100
years.
During a 30‐year mortgage, there’s a 26% chance of experiencing a 100‐year (1%) event.
Annual Exceedance Probability
(AEP)
Chance of occurring in 1
Year
Return Period or Average
Recurrence Interval (ARI)
100% 1 in 1 1‐year50% 1 in 2 2‐year10% 1 in 10 10‐year4% 1 in 25 25‐year1% 1 in 100 100‐year
0.10% 1 in 1000 1000‐year
The “100‐Year” Storm
Historic Rain Events: In Context
E Johnson Street, Madison, WI
Recent Rain Events
July 21, 2016: 2.18” in ~3 hours 20‐50% chance
July 10, 2017: 2.74” in ~2 hours 4‐10% chance
June 16, 2018: 2.49” in ~3 hours 10‐20% chance
August 20, 2018: 5.94” in ~9 hours 0.5‐1% chance
July 9, 2020: 1.72” in ~3 hours 50‐100% chance
All rainfall totals taken from the Weather Underground Sunset Village station (KWIMADIS33) in Madison, WI.
Where the Water GoesWhat’s a watershed?
A watershed is the area of land that drains precipitation (rain, snow, etc.) to a common low point, such as an inlet, stream, or lake.
Determined by surface terrain and underground pipe system.
Where the Water Goes: Sewer Systems Madison has separate
storm and sanitary sewers
Storm sewer system is NOT the same as the sanitary sewer system
https://www.azstorm.org/stormwater‐101/storm‐vs‐sanitary‐sewer
Where the Water Goes: Sanitary Sewer Sanitary sewer drains
residential (toilets, showers, kitchen sinks, etc.), commercial and industrial wastewater streams
Sanitary sewer transports wastewater to Madison Metropolitan Sewerage District (MMSD) treatment plant
Sanitary infrastructure includes: Manholes
Household lateral pipes
Main collector pipes https://www.azstorm.org/stormwater‐101/storm‐vs‐sanitary‐sewer
Where the Water Goes: Storm System Our stormwater drains to
local surface waters
We try to treat for nutrients and sediment
Storm infrastructure includes: Curbs and gutters
Inlets
Pipes
Channels (greenways)
Pondshttps://www.azstorm.org/stormwater‐101/storm‐vs‐sanitary‐sewer
Where the Water Goes: Storm System in Madison
Greenway at Owen Conservation Park
Above: 96” pipe on University Ave (2013)Below: storm sewer inlet on W Doty St
In many watersheds, flooding is not driven by Lake Mendota level
Lake Mendota level: controlled by Dane County Tenney Lock
Yahara Lakes function as a system Solution to problems is increased
conveyance through lake chain
Website: https://lwrd.countyofdane.com/Yahara‐Chain‐of‐Lakes‐Lake‐Levels‐Task‐Force
Reasons for Flooding Issues
https://www.wiscontext.org/yahara‐watershed
Reasons for Flooding Issues Flash flooding: when storm sewer
system cannot handle high amounts of rain
Comparative example: a traffic jam Too many cars of the Beltline during rush hour backups happen
During a storm, more water tries to move through the storm sewer system backups happen
Beltline, looking west from Park Street, WisDOT
Reasons for Flooding Issues Tools have changed in the last five decades.
Old tools made data gathering and stormwater modeling difficult.
VS.
Photo above: https://www.vintag.es/2018/08/life‐before‐autocad.html
Changing public design standards and past limited private design standards have led to flash flooding.
Lax historical building requirements created hard‐to‐solve flooding problems on private property which cannot be easily corrected.
Reasons for Flooding Issues: Changing Design Standards
City of Madison Storm Sewer: 1894‐1960 Rule of thumb design No flood control
City of Madison Storm Sewer: 1961‐1980 Pipes designed for medium‐sized
storms Culverts sized to carry water from
storms with 10% chance of occurring each year
City of Madison Storm Sewer: 1981‐2000 Detention of medium‐sized
storms required for new development
Ponds designed to overflow onto public property
City of Madison Storm Sewer: 2001‐Today Design standards set for storm sewer in enclosed
depressions Culverts sized to convey larger storms (4% chance of
occurrence each year) New development detention requirements increased
Why Replacement Takes Time Road reconstruction, storm sewer is expensive
but long‐lasting Road reconstruction cost = approximately $500‐
$2,000/ft 2% City infrastructure is upgraded annually Average life:
Street=30‐50 years
Pipes=50‐100 years
Storm Water Utility bill 2018 increased 2.3% (avg. residential increase of
$2.15/year) 2019 increased 10.1% (avg. residential increase of
$9.60/year) 96” pipe tunneling on University Ave, Madison, WI (2013)
Watershed Study Goals
Above – Photograph of Actual Flooding Witnessed(June 9, 2020)
Left – Example Watershed Model Output Map(June 9, 2020)
Find out why flooding happens in certain locations
System goals
Eliminate flooding from storm sewer during storms with a 10% chance of occurring each year (4” of rain in a day)
Cars can pass down the middle (highest) part of the street during a storm with a 4% chance of occurring each year (~5” of rain in a day)
Structure and major roadway damage is eliminated for storms with a 1% chance of occurring each year (6.5” of rain in a day)
Flooding extents known during storms with a 0.2% chance of occurring each year (8.96” of rain in a day)
Watershed Study Goals
N. High Point Road at Old Sauk Road, Madison, WI
Find out why flooding happens in certain locations
System goals
Eliminate flooding from storm sewer during storms with a 10% chance of occurring each year (4” of rain in a day)
Cars can pass down the middle (highest) part of the street during a storm with a 4% chance of occurring each year (~5” of rain in a day)
Structure and major roadway damage is eliminated for storms with a 1% chance of occurring each year (6.5” of rain in a day)
Flooding extents known during storms with a 0.2% chance of occurring each year (8.96” of rain in a day)
Watershed Study Goals
Winding Way, Madison, WI
Find out why flooding happens in certain locations
System goals
Eliminate flooding from storm sewer during storms with a 10% chance of occurring each year (4” of rain in a day)
Cars can pass down the middle (highest) part of the street during a storm with a 4% chance of occurring each year (~5” of rain in a day)
Structure and major roadway damage is eliminated for storms with a 1% chance of occurring each year (6.5” of rain in a day)
Flooding extents known during storms with a 0.2% chance of occurring each year (8.96” of rain in a day)
Watershed Study Goals
Regent St at Kenosha Ave, Madison, WI
Find out why flooding happens in certain locations
System goals
Eliminate flooding from storm sewer during storms with a 10% chance of occurring each year (4” of rain in a day)
Cars can pass down the middle (highest) part of the street during a storm with a 4% chance of occurring each year (~5” of rain in a day)
Structure and major roadway damage is eliminated for storms with a 1% chance of occurring each year (6.5” of rain in a day)
Flooding extents known during storms with a 0.2% chance of occurring each year (8.96” of rain in a day)
Watershed Study Goals
Tenney Park, Madison, WI
Find out why flooding happens in certain locations
System goals
Eliminate flooding from storm sewer during storms with a 10% chance of occurring each year (4” of rain in a day)
Cars can pass down the middle (highest) part of the street during a storm with a 4% chance of occurring each year (~5” of rain in a day)
Structure and major roadway damage is eliminated for storms with a 1% chance of occurring each year (6.5” of rain in a day)
Flooding extents known during storms with a 0.2% chance of occurring each year (8.96” of rain in a day)
Find out why flooding happens in certain locations
System goals
Eliminate flooding from storm sewer during storms with a 10% chance of occurring each year (4” of rain in a day)
Cars can pass down the middle (highest) part of the street during a storm with a 4% chance of occurring each year (~5” of rain in a day)
Structure and major roadway damage is eliminated for storms with a 1% chance of occurring each year (6.5” of rain in a day)
Flooding extents known during storms with a 0.2% chance of occurring each year (8.96” of rain in a day)
Watershed Study Goals
Above: Model‐Level Solution EvaluationBelow: Design Level Detail
Test Solutions
Lots more detail gets added in final design
Will help prioritize and budget future projects
Retrofitting infrastructure takes time and moneyRepairs are not always easy, popular, or cheapNot always a good solutionProperty owners will need to create solutions too Solutions will need broad community cooperationGroundwater problems not easily addressed by watershed modeling and surface infrastructure
Watershed Study Limitations
Next Steps
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
Model Existing Conditions & Predict Future Flood Risk
Analyze Solutions on Watershed Scale, Rank & Budget
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
Gather model input data
Install equipment and measure rainfall and channel flow
Build computer models to represent rainfall‐runoff‐routing
Compare model to data
Determine extent of past flooding
Next Steps
Next Steps
Create Drainage Model
What does modeling the Willow Creek watershed involve? Watershed area: 1,953 acres (about 3 square miles)
29 miles of City‐owned storm sewer
400 feet of City‐owned major drainage‐ways (open channels)
About 4,400 parcels, primarily residential
~1475 inlets
What you might see in the watershed
Next Steps
Create Drainage Model
Above: Storm Sewer Flow MeterLeft: Rain Gauge Above: surveyor in the field.
Photo courtesy of Amber Lefers (AE2S).
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
See how well existing storm sewer system meets goals
Next Steps
Commerce Drive near Plaza Drive, Madison, WI
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
Must be holistic
Not “move the problem elsewhere”
Account for climate change
Look at trending increases in storm frequency and intensity
Consider long term maintenance needs
Provide benefits relative to cost
Next Steps
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
Must be holistic
Not “move the problem elsewhere”
Account for climate change
Look at trending increases in storm frequency and intensity
Consider long term maintenance needs
Provide benefits relative to cost
Next Steps
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
Must be holistic
Not “move the problem elsewhere”
Account for climate change
Look at trending increases in storm frequency and intensity
Consider long term maintenance needs
Provide benefits relative to cost
Next Steps
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
Must be holistic
Not “move the problem elsewhere”
Account for climate change
Look at trending increases in storm frequency and intensity
Consider long term maintenance needs
Provide benefits relative to cost
Next Steps
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
Must be holistic
Not “move the problem elsewhere”
Account for climate change
Look at trending increases in storm frequency and intensity
Consider long term maintenance needs
Provide benefits relative to cost
Next Steps
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
What are some general options? Improve pipe and/or inlet capacity
Safe overflow paths
Reroute flow
Increase storage / detention
Flood‐proof buildings
Local landscaping / grading
Solutions on private property to structures or land
Next Steps
CreateDrainage Model
IdentifyFlooding Impacts
Develop Engineering Solutions
Prioritize & Budget
Improvements require time and money Some solutions are long‐term, sustained community efforts (green infrastructure)
Some solutions are discrete, high capital‐cost projects (box culverts, pond, etc.)
Solutions prioritized based on: Frequency, severity and damage (cost‐benefit)
Emergency response routes
Areas with other projects scheduled (road repair, etc.)
Within a Neighborhood Resource Team area
Next Steps
Next Steps
Fall 2020 ‐Winter 2021: Create and
Calibrate Model
Early Spring 2021:Identify Flood
Impacts
Spring –Summer 2021:
2nd Public Meeting
Summer 2021:
Evaluate Solutions
Late Summer 2021:
3rd Public Meeting
Late Fall 2021: Complete
Watershed Study
Property Owner Responsibilities
Self‐report Online Survey: document and share data during rain eventswww.cityofmadison.com/floodingWE NEED YOU TO REPORT ON‐LINE TO INFORM OUR STUDY!
Understand local drainage and how to protect your property
Install backflow preventers and sump pumps
Consider supplemental insurance Focus group participation
Property Owner Responsibilities
Self‐report Online SurveyUnderstand local drainage and how to protect your propertywww.cityofmadison.com/floodprotection
Install backflow preventers and sump pumps
Consider supplemental insurance
Focus group participation
Property Owner Responsibilities
Self‐report Online SurveyUnderstand local drainage and how to protect your property
Install backflow preventers and sump pumps
Consider supplemental insurance
Focus group participation
Property Owner Responsibilities
Self‐report Online Survey
Understand local drainage and how to protect your property
Install backflow preventers and sump pumps
Consider supplemental insurance – contact your private insurance agent for more information
Focus group participation
Property Owner Responsibilities
Self‐report Online Survey
Understand local drainage and how to protect your property
Install backflow preventers and sump pumps
Consider supplemental insurance
Focus group participation: for regional issues that affect more than one person
Property Owner Responsibilities
Be a good neighbor! Understand how your water could have negative impacts on your neighbor’s property.
Install rain gardens and/or rain barrels etc. Have a plan to protect yourself during a flash flood warning.Become a better steward of your watershed.
Adopt an Inlet Remove leaves from the streethttp://www.ripple‐effects.com/
www.cityofmadison.com/flooding
Report Flooding Survey
Individual Watershed Studies Pages
Sign up for updates!
How you can prevent flooding at your home
Everyday Engineering Podcast
Historic Flooding and Basement Drainage episodes
Focus Groups
How to Stay Involved
What is a Breakout Group?
Why Specific Areas?
If your house/business is not within selected area, attend nearby group.
Regardless – please let us know!
Why Attend?
Share Your flooding experiences
Raise maintenance concerns
Breakout Groups
Spring 2021 Present stormwater and flood model findings
Specific to the watershed
Refine data and model
Use as a ‘fact check’ with residents
Next PIM
City Contact Info:
Contact Information
Lauren Striegl Project Manager [email protected] (608) 266-4094
Caroline Burger Watershed Coordinator [email protected] (608) 266-9721
Questions and Answers
Join the Zoom Breakout Room Session Open the Zoom Chat box (if not already
open) Click on Link provided in the Zoom
Group Chat box A message will pop‐up that says “Do
you want to leave this meeting?” Click “Yes” Join Meeting City staff will meet you in the new
virtual meeting room
Focus Groups – Zoom Breakout Rooms
1. Blackhawk Ave
2. Merlham Channel/Robin Greenway
3. Near Campus/University‐Shorewood
4. Shepard/Franklin
5. Sunset Ct
6. University‐Midvale/South Midvale
Focus Groups/Zoom Breakout Sessions